CHEN Ying-lin, LIU Qing
Abstract (
2812 )
This paper introduces the mechanical，thermal and optic properties of a high-impact，transparent styrene-butadiene resin manufactured from the first domestic 10 000-ton facilities, which was compared with those of similar forci}n products. The molecules of the resin contains various segments， such as cis，trans一1，4-butadiene，1，2-butadiene，homo一polystyrene，and random copolymcrizcd blocks of styrene and butadiene. The molecular weight is about 110 000，which can be mono-modal，bi一modal，tri一modal or pent-modal distributed.Both ductile and transparent characters arc achieved. This resin can be processed via traditional injection molding，extrusion，blow molding and thermoforming techniques for products in daily foods and medical areas.
SHAO Hai-ying, SHU Chang, FAN Zhong-yong
Abstract (
2508 )
The crystallization of polycarbonate from melt is rather slow, but it can be greatly enhanced in the presence of proper organic solvents. The crystallization ability and morphology vary with the difference of the physical and chemical properties of the solvents such as the nature, solubility constant and polarity. In this paper, the solvent-induced crystallization behavior of bisphcnol-A polycarbonatc was reviewed.The solvent diffusion kinetics as well as the solvent-induced crystallization kinetics, morphology and mechanism were summarized. The theory and application of the solvent-induced crystallization of bisphcnol-A polycarbonatc were also introduced.
SONG Chang-wen, YAN Hong-xia, LI Peng-bo, LEI Ping-sen
Abstract (
2271 )
Carbon nanotubcs(CNTs) possess unique nanostructure and remarkable mechanical，physical，chemical and electronic properties. These properties make them attractive in many scientific and technological fields such as electronic structures, polymer composites and biological systems. Polymer/CNTs composites have attracted considerable attention of scientists in recent years. However, the poor dispersion of CVTs in organic solvent hinders the realization of their full potential. To overcome this obstack, the surface modification of CVTs becomes essential.In this paper, the structure and property of CNTs were briefly introduced. The methods of the surface modification of CVTs including chemical reaction, surface activation and polymer encapsulation were reviewed. The mechanical，thermal，electronic and friction properties of polymer/CNTs composites were int
DING Yong-Hong, YU Qiang, CHENG Min-lian
Abstract (
1737 )
Based on the special dispersion and swelling characteristics of paraffin in the network of polyethylene (PE)，a polymeric energy storage material was prepared，in which solid-liquid phase change of paraffin served for the latent heat storage, and polyethylene acted as a supporting and encapsulating material.The effect of cross linking degree of PE and temperature on the swelling rate, diffusion kinetics and equilibrium swelling ratio of paraffin were investigated.It showed that the energy-storage performanse could be long-term maintained.
Abstract (
178 )
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The effect of poly(methyl phenylsilsesquioxane)(PMPSQ)on flame retardantrheological, thermal and mechanical properties of polycarbonate(PC) was investigated. As the content of PMPSQ increased from 0 to 5 %the impact strength of PC increased by 71.5 %and the LOI value increased by23%.Further increasing the content ofPMPSQ,no additional improvement was observed.The in-clusion of PMPSQ reduced the glasstransition temperature(T)of PCPMPSQof 5%caused T.of PC decreased from 144.5℃ to 139.1℃.PMPSQ also resulted in reduction of the apparent viscosity of PC and thus enhanced its processability.
WENG Sheng-Guang, CHEN Jian-ding, XIA Zhe-an, ZHANG Sheng-miao
Abstract (
2690 )
Nano-calcium carbonate(nano-CaCO3)particle was surface modified with methacrvlic acid (MAA)in a medium of ethanol.The carboxyl groups of MAA were anchored on the surface of nano-CaCO3 particle and the double bonds were preserved for further reactions. The effects of the dosage of MAA，the pH of the medium, treating time and temperature on the morphology of the modified particles and the stability of the dispersion were investigated in order to optimize modification process.Polystyrene/nano-CaCO3 composites were prepared via in-situ bulk polymerization. TEM showed that nano-CaCO3 particles with diameters less than 100 nm were distributed homogeneously in polymer matrix. When the content of nano-CaCO} was between 7 % and 8，the toughness and tensile strength of the composites reached their maxima, which were 258 % and 311 % that of neat polystyrene, respectively.
DING Zheng-ya, WANG Biao-bing, LI Ying-chun, YANG Yun-feng, HU Guo-sheng
Abstract (
3077 )
High-barrier polyamide 11 /ethylene-vinyl alcohol (PA11/EVOH) copolymer composites were prepared via in situ crosslinking induced by dicumyl peroxide (DCP).The effect of dosage of DCP on the gel content，mechanical property, barrier property and morphology was investigated.It showed that the impact strength, tensile strength and gel content initially increased and then reduced with increasing loading of the DCP. FT-IR analysis indicated that the ester groups were formed from the reaction betwecn carboxyl end groups in polyamidcl l and hydroxyl groups in FVOH. DSC showed that the glass transition temperature(Tg) decreased with increasing DCP content. SFM observation revealed that the DCP loading had a great influence on the morphology of FVOH within PA11 matrix. The discontinuous mutual crossover laminar structure of FVOH was developed when DCP loading was 1 .5，in which the mechanical property and barrier property were improved prodigiously.
WANG Liang, LU Zhong-yuan, WANG Guan-cai
Abstract (
2685 )
Vermiculites were modified by acid treatment and Na ion exchange and was intercalated by hexadecyltrimethylammonium bromide(HDTMA·Br) leading to an organic vermiculite(OVMT). XRD indicated that the layers of vermiculite were dclaminated by HDTMA+ and the spacing distance was increased from 1 .49 nm to 4. 53 nm. Flame-retarded rigid polyurethane foams were prepared by introducing OVMT and ammonium polyphosphate(APP).When 5 % OVMT and 10 APP were introduced from LOI of 26 .8 % was achieved .DSC-TG showed that decalescence temperature was increased 358.1℃to 369.h℃.
Abstract (
84 )
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PHBV decreased after incorporation ofMgO,meanwhile the densi- ty of spherulites increased.The onset thermal degradation temperature of part PHBV matrix in PHBV/ MgOcomposites increased more than 140℃ that of neat PHBVBased on DSC determination,the ef fects of MgOon the crystallization and thermal behavior were considered probably due to the reaction be tween PHBV and MgO occurred at molten state.
XU Li-dan, XIANG Ai-min, QU Xin-hui, WANG Jian-chao, ZHAO Yan
Abstract (
2617 )
Polarizing microscopy and DSC were used to investigate the effect of carbon fiber and talc powder on the crystallization of polvamidc 6.It showed that carbon fiber could lization of PA6.Carbon fiber and talc powder promoted the nucleation in matrix,induce transcrvstal-changed the crystal growth mode, and increased the crystalline rate and the onset crystallization lization temperature.When the cooling rate increased, the onset crystallization temperature was elevated and the degree of crystallinity was also enhanced.
LI Wen-tao, HUO Yin-lei, LIU Xin-lang, ZHANG Xin-chang
Abstract (
3403 )
The mechanical vibration response of a nonlinear system was discussed through the test and analysis of the nonlinear system composed of quality(product)一cushion material(polypropylene foam) under the vibration with sine sweep and fixed frequency. The first harmonic response was analyzed by the method of harmonic balance and obtained the amplitude-frequency response curve of the nonlinear stiffness system and reliable transfer function. The resonating peak of system was influenced by the valuc of the material damp, and the bigger the damp, the smaller the peak value. Based on the mastering of the frequency response curve of polypropylene foam cushion system, the random simple harmonics excitation vibration transmittance could be forecasted and the cushion design could be more reliability based on it.
ZHOU Guo-fa, SU Ting, YAN Li
Abstract (
1745 )
A novel water-assisted c。一injection molding technology was developed，a three-dimensional，unsteady, non-isothermal theoretical model was formulated using volume weighted average ideas. Based on the model，finite clement numerical simulation was carried out to explore the effect of injection temperature on the process of water-assisted co-injection molding. It showed that the core melt pcnctrating depth and width were not affected by water injection temperature. However, the water penetrating depth increased with increasing water injection temperature. The effecting mechanism was discussed based on rhcological theories.
LI Wei, XIE Peng-cheng, DING Yu-mei, YANG Wei-min, CHEN Hong
Abstract (
3124 )
The application of dynamic visualization technique in injection molding process was introduced. Using the visualization experimental equipment in injection molding, the weld line defect was artificially constructed and recorded. The generation mechanism of the defect was analyzed and the weld line defect was depressed by changing processing condition.
ZHANG Xiu-ju, LI N Zhi-dan, ZHENG Bo-wen, ZHOU Chang-ren
Abstract (
2605 )
In order to improve compatibility between hydroxyapatite particles and polylactide in composite bone repair materials, vinyl-terminated polylactide was synthesized.This vinyl-terminated polylactidc was reacted with double bond containing silane, a novel compatilizer was obtained. Through the condenration between the hydroxyl groups hydrolyzed from the silane and those on the hydroxyapatite, the compatibility of polylactidc and hydroxyapatitc was improved.Fouricr Transform Infrared Spectra confirmed the compatilizer possessing designed structure. Scanning Electron Microscope photographs showed that in the composite containing the compatilizer, the border between polylactide and hydroxya-patite became smeared，which was the evidence of improved compatibility.
YAN Bing, LIU Xiao-ming
Abstract (
2588 )
Poly (vinyl chloride) (PVC) was modified with acrylics-g-vinyl chloride copolymer(ACR-g-VC) and its toughness and processability were compared with those modified with impact modifier acrylic rubber(ACR) and chlorinated polyethylene(CPE).It was found that ACR-g-VC and neat ACR possessed similar effects on the processability, but different on toughness. The reason for different behavior was analyzed based on the micromorphologics. In addition, synergistic effect was observed when ACR-g-VC was used together with CPE.
WU Jun
Abstract (
1988 )
Influence of various additives such as softener，foaming agcnt，and assistant foaming agcnt on micro-structurc，appearance，density, and mechanical properties of high density polyethylene (PE-HD) /natural fiber cushioning materials was investigated through hot pressed foaming experiment.The optimum composition was obtained as natural fiber 60 phr，ash stone powder 40 phr，foaming agcnt 15 phr，assistant foaming agcnt 15 phr，plasticizcr 8 phr，softener 63 phr based on 100 parts of PE-HD.The obtained dumping coefficient of PE-HD/natural fiber cushioning materials was 1 .16.
HAN Jian, LIU Chun-tai, DU Yun-hai, SHEN Chang-yu
Abstract (
2643 )
This work explores birefringence behavior for injection molded amorphous polymers. Photo-elasticity method was used to measure the gapwise-averaged birefringence of PS plaque parts molded under different process conditions. The effects of melt temperature and packing pressure on the birefrin-fence distribution were investigated.It was found that residual birefringence decreased from the area near the cavity entrance to the end of the part along the melt flow direction，decreased with incrcasing temperature and decrcasing packing pressure. Especially, higher packing pressure exhibited significant effect on birefringence distribution of the area near the date. Flow-induced residual stress and molecular
orientation distribution of injection molded PS part were evaluated from the birefringence distribution measured by photo-elasticity method.
DU Qiao-lian
Abstract (
2498 )
In this paper an intelligent PITS control arithmetic was provided according to the long delay,time dependence, non linearity and multi-perturbations characteristics of extruders, in order to improve the controlling precision and response speed of the high temperature control system and satisfy the high quality production. It will adjust the extruder temperature according to the section and with different arithmetic,SO that it can not only be equipped with controlling rapidity but also have the retarded controlling stability and anti-Jamming ability. The key points of the intelligent control strategy arc properly divided control interval and the interval parameter validity setting. Finally, it can make the temperature control systems of extruders much more suitable for uncertain circumstance and satisfy the requirement of the temperature control precision.
BI Chao, JIANG Bo
Abstract (
2486 )
In the present study, the flow and mixing characters of the typical screw elements in the reciprocating pin single-screw extruder were studied using a Polyflow finite clement package. Based on the statistical treatment of the flow trajectories for a large number of the mass points which were located at the entrance of the screw clement，the dynamic mixing process was analyzed.Furthermore, the distribution index and the segregation scale were applied to evaluate the distribution mixing and the dispersivc mixing, respectively.At last，the effects of the operating conditions, material viscosity and the pins on the mixing performances of the extruder were also analyzed. Some of the numerical results were com-
pared with previous results.
